St. Landry democrat. (Opelousas, La.) 1878-1894, 1887-07-21


surface being a necessity from water
into the eye. But of all fishes, the
anableps has perhaps the most note
worthy eye. The creature swims half
above the surface of the water, and the
eye is divided horizontally into two
portions, the one for seeing in the
waite, the other in the air. Insects,
again, are provided with the most Won
derful organs of sight. Their nature
and construction are different from all
Others, and two kinds of eyes, the SIM
pie and the composite, are united in
one small creature. The simple eyes
are generally three, and are situated on
the crown of the head between the
more elaborate organs of sight. The
structure of each kind is perfectly
distinct. The composite eyes are
marvellous combination of a null
tiplicity of perfect eyes, which
may be seen in microscopic
examination of the cornea. The cornea
then stands revealed as mass of many
thousand regularly disposed hexagonal
facets, each of which is in itself per-
feet eye. In the head of a butterfly,
nearly thirty-five thousand have been
counted; and some insects are suppos-
ed to be still more numerously sup
piled. The simple eyes, on the other
hand, are simple, as their name i'm.
plies; each simple eye is a single organ
the cornea exhibiting no appearance o:
facets. The uses of these eyes, which
the unwearying researches of natural
lists have now established, are as inter-
esting as they are extraordinary.
Reaumur. in his well-known expert.
ments, first smeared the com
pound eyes of insects with
paint, and next the simple
eyes; and discovered that the COM
pound eyes for horizontal sight, and
the simple for vertical; since those
whose compound eyes were closed
flew straight up into the air until they
were lost to sight, and those whose
simple eyes were operated upon winged
their way on all sides amongst the
flowers around, but neither assembled
into the air nor flew far away. Com
pound eyes, in addition, are supposed.
and with good reason, to have the
power of magnifying; and comical
story is recorded of Puget adjusting
the eye of flea in such way as to see
objects through it, and finding that a
soldier appeared like an army of pig
mics, for what it multiplied it dimin-
ished; and the flame of candle SEEM
ed the illumination of thousand fairy
lamps.
Equally unmistakable evidences of
design are found in the sharpness of
sight accorded to some creatures. and
the deficiency in others. Sir John Lub-
book has shown us how the exception
ally intelligent ant race depends en-
tirely on the sense of smell as guide
to its movement, and that so effectual
and unerring is the sense of smell, that
sight is scarcely needed; and that, in
fact, the workers have in most cases no
vision at all, though they are descended
from flying insects with highly devel-
oped eyes. The antenna have devel-
oped to such an extent as to render
sight a useless adjunct, and where,
through accident or otherwise, the an
tenne are wanting, the ant is 'as help
less as a blind man among ourselves"
The opposite extreme to the ant in
visual sense is to be found in one or
two kinds of birds. A hawk can spy
lark upon piece of earth almost exact
" the same color at twenty times the
distance it is perceptible to a man or
log; a kite soaring out of human sight
can still distinguish and pounce upon
lizards and field mice on the ground;
and the distance at which vultures and
eagles can spy out their prey is almost
Recent discoveries, and
Darwin's observations, have
inclined naturalists to the belief that
birds of prey have not the acute
sense of smell with which they were
once accredited. Their acute sight
seems better to account for their
actions, and they appear to be guided
BY sight alone, as they never sniff any
thing, but dart straight at the object
If their desire. Their counterparts in
he ocean, however, undoubtedly see
md smell equally well, but
are more guided by smell than
sight. In both sharks and rays, the
eyes are good, and have most dis
5inct expression; though, since they
scent their prey from distance, and
swim up to it with great rapidity,
SMELL as Lacepede says, "may be
called their real eye" Smell, in Mr..
Herbert Spsn osr's definition, is antici-
,atary taste; and the manner in which
II rhf az the dominating sense ia suh |